The present invention relates to a device for coating continuous webs with regulable coating strength by means of a doctor rod that rests against the coated side of the web, that is mounted in a doctor bed, and that can be elastically forced with regulable pressure against the web being coated.
The doctor rod in known devices of this type (e.g. German Offenlegungsschrift Pat. No. 3,022,955) is a metering rod mounted in an elastic doctor bed. Between the doctor bed and the bed of the machine is a means of exerting pressure, a compressed-air charged contact-pressure hose for example, that forces the metering rod with variable pressure against the web being coated to control the coating strength and hence the rate at which the coating material flows. Although a metering rod does result in a narrowing coating gap of constant geometry for the coating material, an expanding gap also occurs on the exit side that can lead to surface irregularities in the coating.